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Geohash
Geohash is a public domain geocode system invented in 2008 by Gustavo Niemeyer * * * which encodes a geographic location into a short string of letters and digits. Similar ideas were introduced by G.M. Morton in 1966. It is a hierarchical spatial data structure which subdivides space into buckets of grid shape, which is one of the many applications of what is known as a Z-order curve, and generally space-filling curves. Geohashes offer properties like arbitrary precision and the possibility of gradually removing characters from the end of the code to reduce its size (and gradually lose precision). Geohashing guarantees that the longer a shared prefix between two geohashes is, the spatially closer they are together. The reverse of this is not guaranteed, as two points can be very close but have a short or no shared prefix. History The core part of the Geohash algorithm and the first initiative to similar solution was documented in a report of G.M. Morton in 1966, "A Compu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geocode
A geocode is a code that represents a geographic entity (location or Geographical feature, object). It is a unique identifier of the entity, to distinguish it from others in a finite set of geographic entities. In general the ''geocode'' is a human-readable and short identifier. Typical geocodes (in bold) and entities represented by it: * ''Country code'' and subdivision code. Polygon of the administrative boundaries of a country or a subdivision. The main examples are ISO codes: ISO 3166-1 alpha-2 code (e.g. AF for Afghanistan or BR for Brazil), and its subdivision conventions, such as ISO 3166-2:AF, subdivision codes (e.g. AF-GHO for Ghor province) or ISO 3166-2:BR, subdivision codes (e.g. BR-AM for Amazonas (Brazilian state), Amazonas state). * ''DGG cell ID''. Identifier of a cell of a discrete global grid: a Geohash code (e.g. ~0.023km2 cell 6vd23gq at Brazil's Geographical centre, centroid) or a Open Location Code, Plus Code (e.g. ~0.0002km2 cell 58Q8XXXX+XX with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
